Typical non-contact current sensors capable of measuring direct current (DC) utilize clamp-type or jaw-type sensors having a rigid clamp positionable around an electrical component for measurement. A motor opens and closes the jaws of the clamp and aligns the jaws. Valid measurements require accurate jaw alignment.
Opening the jaws requires a large physical space. In addition, locating a clamp sensor around an electrical component in an electrical panel or other tight space can be awkward or cumbersome for a technician and may cause damage to the electrical component being measured or to nearby components. Vibrations from nearby heavy machinery may exacerbate these problems. Clamp sensors are typically heavier than a standard measurement tool because the jaws include large pieces of iron and a motor for opening, closing, and aligning the jaws.
Rogowski coils are current sensors that are lighter and more flexible than clamp-type current sensors. Rogowski coils are easier to use in tight spaces than most clamp sensors; however, Rogowski coils are not suitable for measuring DC current. A device capable of measuring DC and having a lighter weight and less rigid form factor than a clamp-type meter is desired.